[求助]新手求助~（关于初级的神经网络问题） [复制链接]

各位大虾，我在网上看到的教程里的一个程序段，本来想要试试看的： 6h?gs"[j  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); c5q9LQ/  
net.trainParam.show = 50; |@?%Ct  
net.trainParam.lr = 0.05; _EnwME{@  
net.trainParam.epochs = 300; # ?1Sm/5k`  
net.trainParam.goal = 1e-5; mC&=X6Q]  
p = [-1 -1 2 2;0 5 0 5]; n8=5-7UT  
t = [-1 -1 1 1]; %98' @$:0  
net=train(net,p,t); ]Y6cwZOe  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 \y6OUM2y  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 #Lsnr.80  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 !Bz0^1,L  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 gK#mPcn^  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 ELrsx{p:  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 HCK|~k  
TRAINGD, Performance goal met. V$0dtvGvH  
a = sim(net,p) g71[6<D  
plot(p,t,p,a,'o') kK8itO  
但是为什么老是报错： A[G0 .>Wk  
??? Input argument "net" is undefined. yJuQ8+vgR}